Let’s Kill Hitler. That’s how Stephen Moffat left us hanging back in May. I had visions of the Doctor going on a rampage through history, turning timelines inside out to find the Ponds’ baby. Why that would involve killing Hitler, and whether it was the Doctor who would feel driven to that extremity, I couldn’t guess.

Of course, this is Moffat we’re talking about, so the whole thing turned out to be misdirection. Hitler’s on screen for all of five minutes before Rory bundles him into a cupboard.

Instead, we learn that Amy’s life-long friend Mels, retroactively inserted into her life via a short montage, is the future self of her baby, Melody. After we saw Melody at the end of Day of the Moon, she regenerated one or more times, eventually becoming Mels and inserting herself into the lives of her parents. Think about that. Melody was childhood friends with her parents and played a hand in getting Amy and Rory together.

I have to wonder how far ahead Moffat’s been planning, because I think this was the first mention or appearance of Mels. Maybe he concocted all this just in time for season 6.

As a plan, it makes sense. What better place to lay in wait for the Doctor than in the background of the life of someone who’s intimately tied to him? It makes me wonder when Melody was programmed to kill the Doctor. During her captivity in Florida? Then why didn”t she react more strongly to him at the climax of The Impossible Astronaut? After her regeneration in New York? Did the Silence "reacquire" her after that?

And then Mels regenerates into River Song. Honestly, I was a little disappointed they cut to the chase on this. I had mad visions of a whole string of incarnations hounding the Doctor, slowly learning over time to break the conditioning and become more human.

That development kept the breakneck pace of the episode. A lot of plot wrinkles and developments got thrown into the mix. The Silence is a movement, trying to find "the Question." Time travelers bring justice to criminals who went unpunished in their lifetimes, including both Hitler and River on their to do list.

A lot went on and I found a lot of it unsatisfactory in the amount of coverage it got. Amy’s got a new best friend! Here’s Hitler; now he’s in a cupboard! Melody’s a psychopath! Now she’s less of one!

I’m developing the sense that Stephen Moffat’s making a lot up as he goes along, like inserting Mels into Amy’s life, rather having a masterplan. On the other hand, it’s been pointed out that as a time traveling assassin, Melody/Mels is able to retroactively insert herself into people’s lives, just as the Doctor did to Kazran in A Christmas Carol.

Finally, Rory had the best line of the episode:
AMY: Can you ride a motorbike?